Welding mechanism



Marh 29, 1949. I F. H. JOHNSQN 2,465,456

WELDING MECHANISM Filed Feb. 27, 1946 MV j;

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BY ggd/206V@ Patented Mar. 29, 1949 UNITED s'rATss einem oFFIcE Vi/'ELDNG MECHANISM Frederick H. Johnson, Plea-sant Ridge, Mich.

Application February 27, 1946, Serial No. 650,632

(Cl. 21S-ei) 2 Claims. 1

This invention relates generally to a welding mechanism and more specically to a movable head construction for carrying the movable welding electrode.

One of the primary objects of the present invention is to provide an improved mechanism for carrying the movable welding electrode which will not short the welding circuit due to the depositing of ash metal as a result oi the welding operations.

Another object of the invention is to provide in such a mechanism a structure whereby the insulating members are protected as far as possible from the path of any flash metal which may escape during the welding operation.

Another object of the invention is to provide in such a mechanism structure whereby the relative positions of the electrodes may be adjusted.

Other objects of the invention will become apparent from the following specication, the drawings relating thereto, and the claims hereinafter set forth.

In the drawings, in which like numerals are used to designate like parts in the several views throughout,

Fig. 1 is a partly schematic view oi a welding mechanism showing in longitudinal cross section a Welder head embodying the present invention;

Fig. 2 is a View taken along the line 2-2 of Fig. 1;

Fig. 3 is a View similar to that of Fig. 2, showing a modilied construction.

Referring to the drawings, l indicates a platelike, stationary supporting member which is rigid with the body of the welding machine. An aperture 2 extending through member i adapted l to receive the movable welding head generally designated 3 which carries a welding electrode l co-operable with stationary electrode 5 supported on another portion il of the welding machine body. rihis movable welding head 3 comprises a hollow, cylindrical member l which extends through and substantially lits within the aperture 2 and is held in xed relation with the plate l by a set screw 8 and a split ring 9. The ring 9 is received Within a circumferential recess in the member 'i with one face abutting the lower surface of the member I to hold the member l against upward movement. The upward end of the member 'l away from the member I is sealed by an annular plug lll which has adjacent its lower edge portion an outwardly opening circumferential recess ll which receives a resilient, annular packing or the member 'I to prevent fluid flow between the adjacent portions of member "l and plug lll. Adjacent the upper surface of the plug lil are one or more outwardly opening radially extending apertures which align with aperturesv extending through the member l'. Set screws I3 are threaded within the aligned apertures in member and extend into the registering apertures in the plug lll whereby the plug lll seals the open upward end of member "l, A piston member I4 is positioned within the member l below the plug l@ and has a circumferential annular groove in its outer periphery for receiving an annular packing or gasket member l for preventing fluid liow between the members l and ill. The piston member I l carries a cylindrical thrust member i@ which in turn carries the electrode ll. A central aperture ll' therethrough has a counterbored portion i3 at its upper end for receiving the slotted head of a cap screw ill which is screwthreaded into the member It. A counterbored portion 22 adjacent the lower end of the aperture l'i locates the upper end of the thrust member It. The thrust member It is guided for reciprocating movement adjacent the lower end of member l within an annular member 3U held within the tubular member l adjacent its lower end by a split ring 32. A helical coil compression spring 3d is arranged concentrically with the thrust member lt with its lower end portion seating against the upwardly facing surface of the annular member @il and with its upper end portion seating against the downwardly facing surface of piston member l2 for exerting an upward force on the piston member l2 to urge it toward the plug lll. Fluid pressure is supplied by a conduit 33 held by a conduit fitting 38 screw-threaded within the plug lil as at llt. Fluid supplied by the conduit lli enters the interior of the tubular member 'l intermediate plug ll'l and piston member I4 and exerts a iiuid force against the upper or head portion of the piston member lli which forces the piston member l t downwardly within the member 'l against the upward force exerted by the spring 3d.

The plate member 223 adjustably positions a substantially cubical block d! which carries the electrode whereby the electrode l may be aligned as desired with the electrode 5. This member 28 is welded to the lower end of the thrust member It which extends beyond the lower end of the cylindrical member 'I and is eccentrically positioned with respect to the longitudinal axis of thrust member l ii. A concentric, downwardly extending cylindrical portion l2 of member 28 is received within a cylindrical aperture d4 opening through the top surface 48 of the block 4l. Adjustment of the electrode l is accomplished by rotating the member 2S while holding block 4l against rotation. rl'his movement causes the member 28 to rotate about the longitudinal axis of the member iii. Due to the offset of this axis with respect to the axis of portion e2, the block 4l and electrode will have limited lateral movement. Subsequent to adjustment, the block. il is held in fixed position relative to member 28 by a set screw 49. The cylindrical portion l2 adjacent the set screw i9 is undercut as at 5d so that any roughening or burring of the member d2 caused by the set screw 49 will be below the normal diameter of the member 42 and will not interfere with the insertion or removal of the block 4| from the member 28.

Block 4l has a bottom surface 5l and parallel side surfaces 52 and 5%. An internally screwthreaded aperture t2 opens downwardly through the surface 5! and receives an externally threaded collar member 65 which carries the movable electrode 4. An internally screw-threaded aperture 68 opens outwardly through the surface tlil and is spaced slightly below the top surface 48 for receiving one end of lead cable 'lil' of the secondary circuit of the welding transformer lli. This lead cable lil is preferably of the laminated type with the flat surfaces extending laterally of the axis of the member l and portion l2 whereby the cable 'l0 may be easily flexed in accordance with the longitudinal movement of the head but will. hold the block 4| against rotational movement. the cable is of the circular type which flexes in all directions, then a slotted ber strip li attached to the welding machine body at a convenient location could be used. lf desired, both the :dat lami- .mated cable and strip ll could be used.

As shown, the coolant for the electrode 4 flows within the cable 'lll to a passageway i3 within the block 4l communicating with the hollow interior of electrode 4. A hollow coolant distributing member 'll-'l is arranged concentrically of the threaded aperture 62 and has its upper end portion screw-threaded as at 'i6 into the bottom wall of the aperture 62 so that the hollow member 'J4 is in open communication with the passageway 13. The lower portion of the member le extends downwardly within the hollow portion of electrode 4 and terminates adjacent the end ofv the hollow portion thereof for carrying the coolant from the passageway i3 down into the electrode 4 for cooling thereof. rEhe coolant thus supplied flows upwardly through the annulus formed between the hollow interior of the tip 4 and the outer surface of the tubular member 'I4 toward the bottom of the screw-threaded aperture 52 where it is conducted by means of a passageway il to an internally threaded aperture lil which opens outwardly through the sur-- face 56. The coolant return conduit til is snitably secured in the aperture 'I8 by a conduit attaching connection 82. and extends between the two guiding legs of the strip 'll whereby the block 4i is held against rotation. The other lead cable 84 of the secondary of the welding transformer 'l2 is connected to the electrode 5 which underlies the movable electrode 4 and upon which the work 83 to be welded is placed.

Energization of the welding transformer 'l2 is controlled by means of a suitable switch Sil located in the primary circuit 92: of the transformer 12'. The electrode 5 and work 83 in usual welding practice are grounded to the body of the Welding machine of which the member l is a part. In order to prevent short circuiting of the electrodes Il and 5, it is necessary that there be some sort of insulation between the element carrying the movable electrode 4 and the member I. Therefore, in accordance with the teachings of this invention, I have arranged that the members I4 and' 3Q be fabricated from suitable insulating material such as Gatkef which is a material composed of resin-impregnated cloth or fabric much like the commercial Micarta, both of which may be purchased on the open market.

As shown in Fig. 2, the diameter' of the helical coil spring Se is such that when it is at its eX- treme point of eccentricity with respect to the thrust member Iii, the outer surface of the coils of the spring t4 will not engage the inner walls of the member l. It may now be seen that the members i4 and 3! completely insulate the thrust member le and the attaching screw 20 from electrical contact with any of the metallic members l, plug iii, etc., which are in electrical connection with or in communication with the body of the welding machine, the spring 34 being arranged so that no amount of eccentricity with espect to the thrust member i6 which it can assume is enough for the spring 34 to shortcircuit the thrust member l to the walls of the member l. Furthermore, both the piston member i4 and the annular member 3S are located within the tubular member 1 where it is practically impossible for any flash metal to deposit thereon thereby short out the insulating material.

In lliig. 3 I have shown another arrangement of the dia ieter of the helical coil spring 34 in which arrangement the spring is of sufficiently large diameter so that when it is eccentrically positioned within the tubulainember l, its outer surface engages the inner wall of the member '5 before the inner surface o the spring 3&2 is in engagement with the thrust member i6. A number of schemes for insulating' the mombers have been tried in the prior art, such as placing an insulating sleeve around the tubular member i where it passes through the member l. However, due to the fact that when the machine is ope at d a certain amount of nosh metal will be di. from the pieces being welded, practice has proved that after a period of time this flash metal deposits on the insulating member and continued use of the machine will produce enough flash metal to short-circuit the insulating member. I have provided a novel arrangement of parts in which the insulating members are all located within a metal enclosure, so that any lash metal discharge by the weld cannot deposit on and bridge across the insulating members thereby to short-circuit the welding` electrode in which the movable electrode may be easily adjusted with respect to the stationary electrode, and which is simple and economical of manufacture and trouble-free in operation.

What is desired to be secured by United States Letters Patent is as follows:

l. In an electric welding apparatus, a single unitary member provided with a single continuous cylindrical bore opening outwardly through one end wall thereof, a piston of electrically insulating material slidably positioned within said bore, a piston rod having one end portion directly secured to said piston and its other end extending outwardly of said bore through said end wall, and a single block of electrically insulating material secured Within said bore and having a passage therethrough for slidably accommodating said rod.

2. In an electric welding apparatus, a single unitary member provided with a single continuous cylindrical bore opening outwardly through one end wall thereof, a piston of electrically insulating material slidably positioned within said bore, a piston rod having one end portion directly secured to said piston and its other end extending outwardly of said bore through said end wall, and a single block of` electrically insulating material secured within said bore and having a passage therethrough for slidably accommodating said rod, said block being spaced inwardly in said from receiving and accumulating iiash metal from the welding operation whereby a bridging circuit will not be formed from said rod to said member.

FREDERICK H. J OHN-SON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,046,639 Pierce Dec. 10, 1912 2,063,257 Martin Dec. 8, 1936 2,086,784 Taylor July 13, 1937 Harris Aug. 18, 1942 

